Air circulation controlling arrangement



July 12, 1955 BILLS 2,712,731

7 AIR CIRCULATION CONTROLLING ARRANGEMENT Filed Sept. 8, 1954 INVENTOR.RAYMOND L. DILLS HIS ATTORNEY nited States Patent 0 AIR cmcuLATioNCONTROLLING om mm Raymond L. Bills, Erie, Pa., assignor to GeneralElectric Company, a corporation of New York Application September 8,1954, Serial No. 454,782 8 Claims. (Cl. 62-3) This invention relates torefrigerators and, more particularly, to arrangements for controllingair circulation within refrigerator cabinets.

Household refrigerators of the single-door type which have both a freshfood compartment and a frozen food compartment, are usually cooled by asingle evaporator forming part or all of the wall structure of thefrozen food compartment. The fresh food compartment is of the fresh foodcompartment can be varied by regulating the air flow over theevaporator. One means for controlling this air fiow comprises disposinga bafi'le and damper arrangement between the evaporator and the freshfood compartment. Movement of the damper with ment, which has coolingmeans at the desired temperature. The cooling means is part of arefrigerating system that includes a compressor connected to the coolingmeans by a suction line which has a portion thereof disposed outside thecabinet. The flow of air over the cooling means and through the freshfood compartment is controlled by suitable means, which in turn isgoverned by means responding to the temperature of the portion of thesuction line disposed outside the cabinet. To minimize the transmissionto the responsive means of violent temperature drops in the suctionline, means is interposed between the responsive means and the suctionline.

For a better understanding of the invention reference may be had to theaccompanying drawing, in which:

Fig. l is an elevational view partly in section of a refrigeratorcabinet partly broken away to illustrate the present invention;

Fig. 2 is an elevational view of the back of a refrigerator cabinetembodying the present invention; and

Fig. 3 is an enlarged side elevational view of a portion of Fig. 1.

Referring to the drawing and particularly to Fig. 1, there is shown arefrigerator cabinet 1 having an outer case 2 and an inner liner 3 witha suitable insulation 4 disposed therebetween. The food storagecompartment 5 formed by the inner liner 3 has an access opening that isclosed by a door 6. A sloping bafile 7 is mounted in the storagecompartment 5 to divide the compartment into an upper portion 3 and alower portion It will be understood that this bafile could be horizontalrather than sloping, if desired. An evaporator 10 defining a frozen foodcompartment is disposed in the upper portion 8 of the compartment 5.

Refrigerant is supplied to the cooling means 16 from a compressor 11.The compressor 1?. is connected by suitable means (not shown) to acondenser 52 that is disposed on the back of the refrigerator cabinet 1.The refrigerant flows in a well-known manner from the condenser to thecooling means 10 through a restriction 14 such as a capillary tube. Therefrigerant returns to the compressor 11 from the cooling means it) bythe suc-- tion line 15. As shown in Fig. 2, the restriction 14 and thesuction line 15 are placed in heat exchange relation in order toincrease the efiiciency of the system.

A damper i6 cooperates with the stationary baflie 7 to control air flowin the refrigerator. The bafile 7 is spaced from the door 6 to providean air passage between the door 6 and the battle 7 and the batlle 7 isalso spaced from the back wall of the inner liner 3- to provide apassage between the back Wall of the inner liner 3 and the bafile withthe damper l5 retardhu air flow through the latter passage. Since thearea near the door 6 is warmer than the area near the back wall of theinner liner 3, the normal air flow is down the back Wall of the freshfood compartment and up the area adjacent the door 6 and across thecooling means 16.

When the damper i6 is the position shown in Fig. 1, air circulation issubstantially retarded to prevent the fresh food compartment 5 fromfalling below a predetermined minimum temperature that would freeze thecontents of the compartment When the damper i6 is in the phantom lineposition shown in Fig. 3, the air may circulate freely through the freshfood compartment 5 over the evaporator it; to provide the maximumcooling effect to the fresh food compartment 5 from the evaporator 10.

In order to prevent the damper place against the bafile 7, it will beobserved that the edge of the damper 16 never makes physical contactwith the bafile 7 but is spaced slightly therefrom. Whether the damper16 is in an open or closed position, it will be seen that it is alwayson a slope so that any water deposited thereon will run 0E and notfreeze on the damper 16.

16 from freezing in including a bellows 17, a temperature responsivebulb 18, and a connecting tube 19. The bulb 18 is located in a fin 24)that is fastened to the portion of the suction tube 15 of therefrigerating system outside the cabinet 1. The bulb 18 is spaced fromthe suction line 15 a predetermined distance with a portion of the findisposed therebetween. The distance between bulb l8 and the suction line15 is determined by the rate of heat transmission desired from thesuction line 15 to the bulb 18.

The temperature of the gas passing through the suction line variesdepending on the load on the refrigerator; a heavy load on therefrigerator resulting in a high temperature and a light load resultingin a low tempera- The control system for the bellows is designed so thatthe damper 16 is actuated to an open position when the suction line 15has a high temperature and to a closed position when the suction linehas a low temperature.

Thus, it will be seen that the bulb 3.8 could ordinarily be placed indirect contact Wi'h the suction line 15 to reflect the temperaturethereof to move the damper to its desired position. However, there is anoccasional surge of liquid refrigerant through the suction line 15resulting in a violent temperature drop. If the bulb in direct contactwith the suction line 15. it will be readily 13 were placed observedthat the violent temperature drop in the suction line would betransmitted to the bulb 18 whereby the damper 16 would be moved to aclosed position even though conditions required the damper 16 to be inits open position. Thus, the fin serves to prevent this undesired surgeactuation of the damper 16, and yet permits the general suction linetemperature to govern the position of the damper 16.

To obtain this desired action, the fin or bracket 20 can, for example,be made of steel .060" thick with the bulb 18 being spaced 1 /2 from thesuction tube 15 in the fin 20. This arrangement permits heat to betransmitted from the suction line 15 to the bulb 18 at the desired rateto cause the bellows 17 to actuate the damper 16 in response to generalsuction line temperatures but'prevents the violent temperature drops inthe suction line resulting from liquid refrigerant momentarily flowingtherethrough from being transmitted to bulb 18 actuating the damper 16.Thus, the spacing obtained by the fin prevents the undesired movement ofthe damper to its closed position when a surge of liquid refrigerantpasses through the suction line but does cause the bulb 18 to sensenormal or continuing changes in the suction line temperature so that thedamper will close when the temperature of the suction gas passingthrough the suction line drops due to a decrease in load on therefrigerator.

As the purpose of the fin is to control the rate at which the heat inthe suction line 15 is transmitted to the bulb 18, it will be obviousthat the fin may be made of any of a number of heat conducting materialsprovided the dimensions thereof including cross-sectional area andlength between tube 15 and bulb 18 are varied accordingly to permit theproper rate of heat transfer therebetween. For example, when aluminum isemployed instead of steel, the thickness of the fin between the tube 15and the bulb 18 would be reduced to approximately .020 for the samespacing of 1 /2". It will be seen that by maintaining the same rate ofheat transmission regardless of the material of the fin that the bellowswill be moved the same distance by the same temperature change in thesuction line. The use of the fin 20 results in the damper 16 openingwhen the refrigerator is under a heavy load and closing when therefrigerator is under a light load.

The bellows 17 is positioned within a casing 21 that is disposed betweenthe inner liner 3 and the outer case 2 of the refrigerator cabinet. Thebellows 17 is connected to a member 22 at a raised portion 23 of themember 22. The member 22 is secured to a second member 24, which ispivotally mounted at 25 on the casing 21. An arm 26 is connected to thesecond member 24 at a point remote from the pivot point 25 and extendsthrough an opening in the inner liner 3. The damper 16 has a stud 27which fits in the slot in the end of the arm 26 as shown in Fig. 3. Apair of brackets 23 are connected to the inner liner 3 and have a stud29 therebetween that serves as a pivot for the battle. The open andclosed positions of the bafde are controlled by the mechanical leverageratio between the bellows 17 and arm 26. This ratio could be varied toprovide the desired opening and closing positions.

Considering the operation of the apparatus, the damper 16 is in itsclosed position when the bellows 17 is contracted. Under conditions ofrelatively light load on the refrigerator, the temperature of thesuction line will be at a low point in its range and the bellows 17 willaccord ingly be contracted so that the damper 16 will be in its closedposition. As the load on the refrigerator increases, the temperature ofthe suction line 15 increases and causes an expansion of the charge inthe closed system resulting in an expansion of the bellows 17. Theexpansion of the bellows 17 results in the second member 24 pivotingabout point 25 to move the arm 26 whereby the damper 16 is moved to thephantom line position. This produces an increased amount of aircirculation through the refrigerameans and said suction tor. Thisincreased circulation of air over the cooling means 10 and through thefresh food compartment'S provides more effective cooling of thecompartment 5 and enables the maintenance of a substantially constanttemperature therein despite the increase in the load. The oppositeshifting of the bellows occurs upon a decrease in load resulting from adecrease in the suction line temperature, which is transmitted throughthe fin 20. This contraction of the bellows 17 results in a reduction inthe amount of air circulated over the cooling unit and through thecompartment 5 so that the danger of freezing fresh food stored 'withinthe fresh food compartment 5 is minimized.

The present invention has the advantage of controlling the circulationof air within the fresh food compartment in response to the suction linetemperature, which is the temperature that will indicate an increasedload more quickly than any other portion of the refrigerating system.The fin of proper thermal conductivity permits the minimization of thesurging temperature of the suction line so that the suction linetemperature may be employed to control the amount of air circulatedthrough the fresh food compartment.

While the present invention has been described by.

reference to a particular embodiment thereof, it will be understood thatmodifications may be made by those skilled in the art without actuallydeparting from the invention. Therefore, the appended claims areintended to cover all such variations as come within the true spirit andscope of the invention.

I claim:

1. In a refrigerator having a cabinet providing a food storagecompartment, a refrigerating system including cooling means for saidcompartment and a compressor, a suction line connecting said coolingmeans and said compressor, a portion of said suction line being disposedout- 7 side said cabinet, means for controlling flow of air over saidcooling means and through said compartment, means responsive to thetemperature of the portion of said suction line disposed outside saidcabinet for controlling the position of said air controlling means, andmeans disposed between said responsive means and said suction line andin heat exchange relation with said responsive means and said suctionline to minimize the transmission to said responsive means of violentmomentous temperature fluctuations in said suction line.

2. A refrigerator including a refrigerating unit, a food storagecompartment and cooling means for said compartment, a suction lineconnecting said cooling means and said refrigerating unit, means withinsaid compartment defining a passage for air circulating over saidcooling means and through said compartment, means for controlling flowof air through said passage, means responsive to the temperature of saidsuction line for controlling the position of said air controlling means,and means disposed between said responsive means and said suction lineand in heat exchange relation with said responsive means and saidsuction line to minimize the transmission to said responsive means ofviolent temperature drops in saidsuction line.

3. In a refrigerator having a cabinet providing a food storagecompartment, a refrigerating system including cooling means disposed inthe upper portion of said compartment, a baffle spaced from thebottorn'of said cooling means and extending across the width of saidcompartment, said baffle extending substantially the entire depth ofsaid compartment,

for controlling the circulation of air therethrough, means a responsiveto the temperature of the suction line of said refrigerating system forcontrolling the position of said damper, and means disposed between saidresponsive line and in heat exchange relaand being spaced from the backof said compartment to provide a passage for 5 tion with said responsivemeans and said suction line to minimize the transmission to saidresponsive means of violent temperature drops in said suction line.

4. In a refri erator having a cabinet providing a food storagecompartment, a refrigerating system including cooling means disposed inthe upper portion of said compartment and a compressor, a suction lineconnecting said cooling means and said compressor, a portion of saidsuction line being disposed outside said cabinet, a bafiie spaced fromthe bottom of said cooling means and extending across the Width or saidcompartment, said bafile ext nding substantially the entire depth ofsaid compartment and being spaced from the back of said compartment toprovide a passage for air circulating within said compartment and oversaid cooling means. a damper disposed within said passage forcontrolling the circulation or" air therethrough, means responsive tothe temperature of the portion of said suction line disposed outsidesaid cabinet for controlling the position of said damper, and meansdisposed between said responsive means and said suction line and in heatexchange relation with said responsive means and said suction line tominimize the transmission to said responsive means of violenttemperature drops in said suction line.

5. In a refrigerator having a cabinet providin a food storagecompartment, a refrigerating system including cooling means for saidcompartment and a compressor, a suction line connecting said coolingmeans and said compressor, a portion of said suction line being disposedoutside said cabinet, means Within said compartmerit defining a passagefor air circulating over said cooling means and through saidcompartment, a damper for controlling the flow of air through saidpassage, a bellows connected to said damper to actuate said damper,temperature responsive means connected to said bellows, and a findisposed in heat exchange relation with said portion of said suctionline disposed outside said cabinet, said temperature responsive meansbeing disposed in heat exchan e relation with said fin, said temperatureresponsive means being responsive to the suction line temperature tocause the bellows to actuate the damper to control the flow of airthrough said passage, said fin minimizing the transmission to said ternerature responsive means of violent temperature drops in said suctionline.

6. In a refrigerator having a cabinet providing a food storagecompartment, a refrigerating system including cooling means for saidcompartment and a compressor, a suction line connecting said coolingmeans and said compressor, a portion of said suction line being disposedoutside said cabinet, means Within said compartment defining a passagefor air circulating over said cooling means and through saidcompartment, a damper for controlling the flow of air through saidpassage, a bellows connected to said damper to actuate said damper,tenperature responsive means connected to said bellows, and a findisposed in heat exchange relation with said 6 line disposed outsidesaid cabinet, said fin having a low thermal conductivity, saidtemperature responsive means being disposed in heat exchange relationwith said fin, said temperature responsive means being responsive to thesuction line temperature to cause the bellows to actuate the damper tocontrol the flow of air through said passage, said fin minimizing thetransmission to said temperature responsive means of violent temperaturedrops in said suction line.

7. In a refrigerator having a cabinet providing a food storage comartment, a refrigerating system including cooling means for saidcompartment and a compressor, a s ction line connecting said coolingmeans and said eressor, a portion of said suction line being disposedoutside said cabinet, means Within said compartment defidng a passagefor air circulating over said cooling is and through said compartment, adamper for controlling how of air through said passage, temperatureresponsive means connected to said damper to actuate per, and a findisposed in heat exchange rela- .i said portion of said suction linedisposed ou' ide said cabinet, said temperature responsive means beingdisposed in heat exchange relation with said fin, said temperatureresponsive means being responsive to the suction line temperature toactuate the damper to control the flow of air through said passage, saidfin minimizing the transmission to said temperature responmeans ofviolent temperature drops in said suction line.

8. In a refrigerator having a cabinet providing storage compartment, 2:refrigerating system including cooling means for said compartment and acompressor, a suction line connecting said cooling means and saidcompressor, a portion of said suction line being disposed outside saidcabinet, means within said compartment defining a passage for aircirculating over said cooling means and through said compartment, adamper for con trolling flow of air through said passage, temperatureresponsive means connected to said damper to actuate said damper, and afin disposed in heat exchange relation with said portion of said suctionline disposed outside said cabinet, said fin having low thermalconductivity, said temperature posed in neat exchange relation With saidportion or" said suction a food passage, said fin minimizing thetransmission to said temperature responsive means of v1olent temperaturedrops in said suction line.

References Cited in the file of this patent UNITED STATES PATENTS

